The present invention relates to a system and method for digital video broadcast handheld (DVB-H) datagram de-encapsulation.
DVB-H is a new European Telecommunications Standards Institute (ETSI) standard for providing Digital Video Broadcasting (DVB) services to handheld devices (e.g., mobile phones), see Digital Video Broadcasting (DVB); DVB-H implementation Guidelines, ETSI TR 1XX XXX V0.1.0 (2004-09), the entire contents of which are hereby incorporated by reference. Provisions are made in this standard to support low-power receiver implementations. As with the prior ETSI standards DVB-S, C, and T, in DVB-H information is broadcast in so-called Transport Streams in which typically several MPEG-2 encoded Programs are multiplexed.
DVB-H is based on DVB-T, and is fully backwards-compatible. DVB-H provides additional features to support handheld portable and mobile reception that allows power saving, mobility with high data rates, single antenna reception, and SFN networks, among others. DVB-H also provides impulsive noise tolerance and increased general robustness as well as support for seamless handover during power off-times.
All of the foregoing features are achieved by adding options to DVB-T including, but not limited to, time-slicing for power saving, MPE-FEC frames (explained below) for additional robustness, and a 4k mode for mobility and network design flexibility. In DVB-H, data is bundled in “bursts” at a high rate so that it is possible to switch off the receiver between bursts, realizing up to 90% energy savings. Time-slicing also permits a simple handover during absence of the service. In order to establish a convergence between the traditional broadcast world and the PC world, IP encapsulation is introduced. To extend this to the small multimedia devices, IP encapsulation is combined with time-slicing. DVB-H is meant for IP-based services using Multi Protocol Encapsulation (MPE). Additional robustness is provided to the DVB-H system by protecting the MPE-sections with an extra layer of Forward Error Correction (FEC) coding, thus the nomenclature MPE-FEC frame. DVB-H can share DVB-T multiplex with MPEG2 services.
An MPE-FEC frame 100 comprising an Application data table 101 and a Reed-Solomon (RS) data table 102 is specified in the ETSI standard as the transmission frame format, see FIG. 1. In a straightforward approach to IP datagram de-encapsulation, all locations in the MPE-FEC frame that correspond to an incorrectly received IP datagram are marked as erasures. Since IP datagrams can have a size up to 4080 bytes, large parts of an MPE-FEC frame may be erased in this way. Similarly, the data in the Reed Solomon data table, which is transmitted on a per column basis in so called MPE-FEC sections, can lead to erased parts of 1024 bytes (in general the erased parts are equal to the number of used rows in an MPE-FEC frame). So, a straightforward solution is neither effective nor efficient.
A technique is needed for processing received MPE-FEC frame data that allows only a part of the symbols of an IP datagram and the Reed Solomon data to be marked as an erasure for the MPE-FEC decoder.